Background Anthonomus grandis grandis is the main cotton pest in the Americas,with the potential to become a pest in other continents.The insect uses the plant's reproductive organs for feeding,oviposition,and sur...Background Anthonomus grandis grandis is the main cotton pest in the Americas,with the potential to become a pest in other continents.The insect uses the plant's reproductive organs for feeding,oviposition,and survival strategies in the off-season,sheltering in dry bolls.This study aimed to know the reproductive potential,feeding,longevity,and morphometric characteristics of boll weevils from dry bolls,squares,and traps.Adults were obtained from infested squares,dry bolls,and traps installed in cotton fields and the Caatinga area.Thirty weevil pairs were maintained in the laboratory to assess the oviposition,feeding holes,longevity,and morphometric measurements of the parental and F_(1) generations.Results In the parental generation,boll weevils from traps(the Caatinga area and cotton cultivation)showed greater reproductive potential.Boll weevils from squares and the Caatinga area showed greater feeding activity compared with those from cotton cultivation.Greater rostrum length,thorax+abdomen length,and abdomen width were observed in boll weevils from cotton cultivation and dry bolls.The origin of boll weevils parental generation did not affect progeny emergence time.The F_(1) generation of boll weevils showed significant differences in average longevity depending on the origin of different microhabitats.Furthermore,differences in rostrum lengths were observed,with the boll weevils coming from traps installed in cotton cultivation,the Caatinga area,and dry bolls being the largest.Regarding thorax+abdomen length and abdomen width,the highest values were observed in those from the Caatinga area and cotton cultivation.Conclusion It was proven that dry bolls did not affect the reproductive,feeding,and longevity performance of boll weevils,enabling better insect fitness(reproduction and size)in relation to those coming from squares.The use of dry bolls as off-season shelter is an important survival strategy for the boll weevil.展开更多
The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were colle...The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.展开更多
Rice leaffolder, Cnaphalocrocis medinalis, is one of the major foliage feeders found in the rice growing regions in India. When the crop was at maturity, numerous adults of rice leaffolder were found in the rice field...Rice leaffolder, Cnaphalocrocis medinalis, is one of the major foliage feeders found in the rice growing regions in India. When the crop was at maturity, numerous adults of rice leaffolder were found in the rice fields though the larval population gradually decreased, and no eggs were found on rice leaves. The population characteristics of C. medinalis were assessed based on the physiological age status of adults at different crop growth stages. Based on egg development within ovarioles, ovariole appearance number and colour of fat bodies, and characteristics of bursa copulatrix, physiological age status of the adults was described, which served as a basis for the determination of age composition. C. medinalis adults were found during the first week of August on rice plants, of which 44% were in Age 0 with immature ovaries, indicating immigrants. However, 28% adults each were at Ages 1-2 with developing ovaries, indicating local breeding population. The carryover and off-season survival of C. medinalis were also studied to determine the contribution of the alternative hosts in the population growth that helped in devising efficient management strategies. Rice was the most preferred host followed by Triticum aestivum, Echinochloa crusgulli and Brachiaria plantaginea. Various routes of the carryover of C. medinalis from season to season were discussed.展开更多
基金supported by Fundacao de Amparoà Pesquisa do Estado da Bahiathe Coordenacao de Aperfeicoamento de Pessoal de Nível Superior Foundation(Finance Code 001)for financial supportBahia Association of Cotton Producers。
文摘Background Anthonomus grandis grandis is the main cotton pest in the Americas,with the potential to become a pest in other continents.The insect uses the plant's reproductive organs for feeding,oviposition,and survival strategies in the off-season,sheltering in dry bolls.This study aimed to know the reproductive potential,feeding,longevity,and morphometric characteristics of boll weevils from dry bolls,squares,and traps.Adults were obtained from infested squares,dry bolls,and traps installed in cotton fields and the Caatinga area.Thirty weevil pairs were maintained in the laboratory to assess the oviposition,feeding holes,longevity,and morphometric measurements of the parental and F_(1) generations.Results In the parental generation,boll weevils from traps(the Caatinga area and cotton cultivation)showed greater reproductive potential.Boll weevils from squares and the Caatinga area showed greater feeding activity compared with those from cotton cultivation.Greater rostrum length,thorax+abdomen length,and abdomen width were observed in boll weevils from cotton cultivation and dry bolls.The origin of boll weevils parental generation did not affect progeny emergence time.The F_(1) generation of boll weevils showed significant differences in average longevity depending on the origin of different microhabitats.Furthermore,differences in rostrum lengths were observed,with the boll weevils coming from traps installed in cotton cultivation,the Caatinga area,and dry bolls being the largest.Regarding thorax+abdomen length and abdomen width,the highest values were observed in those from the Caatinga area and cotton cultivation.Conclusion It was proven that dry bolls did not affect the reproductive,feeding,and longevity performance of boll weevils,enabling better insect fitness(reproduction and size)in relation to those coming from squares.The use of dry bolls as off-season shelter is an important survival strategy for the boll weevil.
文摘The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.
基金supported by Indian Council of Agricultural Research, National Agricultural Innovative Project (Grant No.C2046)
文摘Rice leaffolder, Cnaphalocrocis medinalis, is one of the major foliage feeders found in the rice growing regions in India. When the crop was at maturity, numerous adults of rice leaffolder were found in the rice fields though the larval population gradually decreased, and no eggs were found on rice leaves. The population characteristics of C. medinalis were assessed based on the physiological age status of adults at different crop growth stages. Based on egg development within ovarioles, ovariole appearance number and colour of fat bodies, and characteristics of bursa copulatrix, physiological age status of the adults was described, which served as a basis for the determination of age composition. C. medinalis adults were found during the first week of August on rice plants, of which 44% were in Age 0 with immature ovaries, indicating immigrants. However, 28% adults each were at Ages 1-2 with developing ovaries, indicating local breeding population. The carryover and off-season survival of C. medinalis were also studied to determine the contribution of the alternative hosts in the population growth that helped in devising efficient management strategies. Rice was the most preferred host followed by Triticum aestivum, Echinochloa crusgulli and Brachiaria plantaginea. Various routes of the carryover of C. medinalis from season to season were discussed.
